The root cause of this error is that for future entries there will be no BlogsStatsUser record created. Digging into the issue revealed some more problems around future blog entries:

When adding a future blog entry, in the Recent Bloggers portlet there will be no record created when we reach the display date

In the activities portlet there will be an activity for the future entry - it shouldn't display anything until the entry becomes visible.

Future blog entries are being indexed automatically and a search portlet will pop those up but it shouldn't.

Create a blog entry with a display date now, then create a second blog entry in the future. A guest can go to the page clicking on the displayed blog entry and click on the next link at the bottom of the page and it will show the guest the second future blog entry. This guest can even comment on the future entry or use one of the social links (tweet, facebook like, etc)